Three logically and empirically independent issues are often conflated in t
heory acid research on brain and language: localization, innateness, and do
main specificity. Research on adults and infants with focal brain injury su
pport the following conclusions: (a) linguistic knowledge is not innate, an
d it is not localized in a clear and compact, form in either the infant or
adult brain; (b) the infant brain is not, however, a tabala rasa-it is alre
ady highly differentiated at birth, and certain regions are biased from the
beginning toward modes of information processing that are particularly use
ful for language, leading tin the absence of local injury to the standard f
orm of brain organization for language; (c) the processing biases that lead
to the "standard brain plan" are innate and localized, in both infants and
adults, but they are not specific to language; and (d) the infant brain is
highly plastic, permitting alternative "brain plans" for language to emerg
e if the standard situation does not hold. (C) 1999 by Elsevier Science Inc
.